Mesostructured transition aluminas

Abstract

Mesoporous crystalline alumina compositions and process for the preparation thereof are described. The compositions are useful as catalysts and absorbents.

1. A mesostructured crystalline hydrated alumina composition consisting essentially of boehmite with atomically ordered crystalline framework walls forming mesopores, without amorphous hydrated alumina, and exhibiting at least one low angle x-ray diffraction line corresponding to a lattice spacing of at least 2.0 nm and multiple wide angle x-ray diffraction lines with CuKα radiation wherein λ is 0.1541 nm and the boehmite particularly has characteristic 2θ/° diffraction lines of the multiple wide angle lines as shown in  FIGS. 2 and 5  marked “As-made” and  7 B marked “MSU-S/B” corresponding to an ordered lattice comprised of oxygen atoms and hydroxide groups with aluminum in interstitial positions within the lattice, wherein the surface area is at least 200 cm 2 /g; and wherein the pore volume is at least 0.40 cm 3 /g, wherein the boehmite is formed by mixing a precursor amorphous hydrated alumina and an organic modifier which forms the mesostructure and then heating the mixture so that the boehmite is completely formed and then removing water and the organic modifier to provide the composition which can be calcined to form a transition alumina. 
     
     
       2. A mesostructured crystalline hydrated alumina composite composition with mesopores containing an organic modifier in the mesopores of the alumina wherein the alumina composition consists essentially of boehmite with atomically ordered crystalline framework walls forming mesopores, without amorphous hydrated alumina, and when the organic modifier is removed exhibits at least one low angle x-ray diffraction line corresponding to a lattice spacing of at least 2.0 nm and multiple wide angle x-ray diffraction lines and the boehmite particularly has characteristic 2θ/° diffraction lines of the multiple wide angle lines as shown in  FIGS. 2 and 5  marked “As-made” and  7 B marked “MSU-S/B” as made corresponding to an ordered lattice comprised of oxygen atoms and hydroxide groups with aluminum in interstitial positions within the lattice, wherein the boehmite is formed by mixing a precursor amorphous hydrated alumina and the organic modifier which forms the mesostructure and then heating the mixture so that the boehmite is completely formed to provide the composition, wherein when the organic modifier is removed, the composition can be calcined to form a transition alumina. 
     
     
       3. The composition of  claim 2  wherein the organic modifier is a nonionic surfactant. 
     
     
       4. The composition of  claim 3  wherein the surfactant is selected from the group consisting of a polyethylene oxide block co-polymer, an alkylene amine; an alkylene polyamine, a polypropylene oxide amine, a polypropylene oxide polyamine and mixtures thereof. 
     
     
       5. The composition of any one of  claims 2 ,  3  or  4  wherein the hydrated alumina, component is boehmite. 
     
     
       6. A mesostructured crystalline transition alumina composition comprising gamma alumina and:
 wherein the composition exhibits at least one low angle x-ray diffraction line corresponding to a lattice spacing of at least 2.0 nm and derived from a boehmite with atomically ordered crystalline framework walls forming mesopores, without amorphous hydrated alumina, with multiple wide angle x-ray diffraction lines with CuKα radiation wherein λ is 0.1541 nm and the boehmite particularly has characteristic 2θ/° diffraction lines of the multiple wide angle lines as shown in  FIGS. 2 and 5  marked “as-made” and  7 B marked “MSU-S/B” as made corresponding to an ordered oxygen atom lattice with aluminum in interstitial positions within the lattice, wherein the surface area is at least 200 m 2 /g; and wherein the pore volume is at least 0.40 cm 3 /g, wherein the boehmite is formed by mixing a precursor amorphous hydrated alumina with an organic modifier which forms the mesostructure, heating the solution so that the boehmite is completely formed, then removing water and the organic modifier from the mesostructured boehmite, and then calcining the mesostructured boehmite to form the gamma alumina composition. 
 
     
     
       7. The mesostructured transition alumina of  claim 6  wherein the transition alumina consists essentially of gamma alumina.